Screening for Cytogenetic and Molecular Chromosome Rearrangements in Tunisian Children With Conotruncal Heart Defects

Abstract : Background. Conotruncal heart defects are cardiovascular malformations that have most been associated with chromosomal 22q11.2 microdeletion. Methods. To estimate frequency and investigate the clinical features of these microdeletions in unselected patients with conotruncal heart defects, a total of 26 patients originating from southern Tunisia had been prospectively evaluated through cytogenetic and molecular studies. The clinical analysis was performed according to a specific clinical protocol for the diagnosis of congenital cardiovascular malformations. A molecular cytogenetic technique was undertaken by fluorescence in situ hybridization (FISH) using 2 probes: LSI DiGeorge N25 (D22S75) region probe N25/ARSA, and LSI DiGeorge/VCFS region probe TUPLE1/ARSA. cytogenetic analysis with RHG banding was carried out to detect chromosome rearrangements. All patients have normal karyotype 46,XX or 46,XY. Results: The frequency of the 22q11.2 microdeletion in the subjects carrying conotruncal heart defects with or without extracardiac signs of our series is thus estimated at 3.85% (1/26). Conclusion: The microdeleted subject is carrying a tetralogy of Fallot.